Excessive exposure to sunlight increases the risk of skin cancer because some of the photons have enough energy to break chemical bonds in biological molecules. these bonds require approximately 250–800 kj/mol of energy to break. the energy of a single photon is given by e=hc/λ where e is the energy of the photon in j, h is planck’s constant (6.626×10−31 j⋅s), and c is the speed of light (3.00×108 m/s). determine which kinds of light contain enough energy to break chemical bonds in biological molecules by calculating the total energy in 1 mol of photons for light of each wavelength. infrared light (1500 nm) visible light (500 nm) ultraviolet light (150 nm)

b.transmitters send radio waves, and receivers capture radio waves.

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia

a sonic boom is a loud boom that breaks the sound barrier

explanation: